1. Field of the Invention
The present invention relates to a dye for a dye sensitized photovoltaic cell and a dye sensitized photovoltaic cell including the same. More particularly, the present invention relates to a dye which implements an open circuit voltage, which dye includes a metal composite with an imidazolium, pyridinium, pyrrolidinium, or quinolidinium cation. The invention is also directed to a dye sensitized photovoltaic cell including such a dye and showing improved photoelectric efficiency.
2. Description of the Related Art
Diverse research has been conducted in an attempt to develop energy sources to replace conventional fossil fuels and address approaching energy crises. Particularly, extensive research is being conducted into uses for alternative energy sources (such as wind power, atomic power, and solar power) as substitutes for petroleum resources, which are expected to be used up within several decades. Among these alternative energy sources, photovoltaic cells using solar energy are available and environmentally friendly, unlike other energy sources. Since the development of Se photovoltaic cells in 1983, photovoltaic cells have drawn much attention. Recently, Si photovoltaic cells have drawn attention from researchers.
However, the practical use of Si photovoltaic cells is difficult because of high production costs and difficulties in improving cell efficiency. To address these problems, researchers have been studying and developing dye sensitized photovoltaic cells that can be produced at reduced cost.
Unlike Si photovoltaic cells, dye sensitized photovoltaic cells are electrochemical photovoltaic cells that mainly comprise photosensitive dye molecules (which absorb visible rays and produce electron-hole pairs) and transition metal oxides (which transfer the produced electrons). Among conventional dye sensitized photovoltaic cells are dye sensitized photovoltaic cells using nano titanium oxide (i.e., anatase). Dye sensitized photovoltaic cells can be produced at low cost. Also, since dye sensitized photovoltaic cells use transparent electrodes, they can be applied to external glass walls of buildings or glass greenhouses. However, dye sensitized photovoltaic cells have low photoelectric efficiency, thereby limiting their practical applications.
The photoelectric efficiency of photovoltaic cells is proportionate to the quantity of electrons produced from the absorption of solar beams. Thus, to increase the photoelectric efficiency, the quantity of electrons should be increased. Alternatively, the produced and excited electrons should not be used in electron-hole recombination. The quantity of produced electrons can be increased by raising the absorption of solar beams or the dye adsorption efficiency.
To increase the dye adsorption efficiency per unit area, nano-sized particles of oxide semiconductors have been prepared. To increase the absorption of solar beams, the reflectivity of platinum electrodes has been increased or micro-sized oxide semiconductor light scattering agents have been included. However, these conventional methods have limited impact in increasing the photoelectric efficiency of photovoltaic cells. Accordingly, a need exists for new technology capable of improving photoelectric efficiency.
The information disclosed in this Background section is presented to further the understanding of the present invention. Applicant does not admit that all information disclosed in this Background section is prior art to the present invention.